Cross linking of crystalline polymers with sulfur and a polyhaloaliphatic compound



' mite This invention relates to polymers or copolymers cured by sulfur and a polyhaloaliphatic compound, the present application being a continuation-in-part of SN. 177,179, filed Mar. 5, 1962.

It has heretofore been known to vulcanize high unsaturation rubber, such as natural rubber, with sulfur and certain mild accelerators such as guanidine derivatives and thiazole derivatives. Low unsaturation rubbers have been vulcanized with somewhat greater difliculty by the use of sulfur, zinx oxide and accelerators or greater activity, such as thiuram derivatives and dithiocarbamates.

Additionally it has been shown in copending S.N. 177,- 179 that it is possible to formulate a vulcanizing mixture which will cure not only high unsaturation and low unsaturation elastomers but, surprisingly, elastomers of no unsaturation as well. More specifically, it has been found that elastomers and especially saturated elastomers may be cured with sulfur and a polyhaloaliphatic compound of the class consisting of polyhaloalkanes and polyhalocyclomonoalkenes. This is particularly surprising in view of the fact that sulfur in combination with polyhalocyclodiolefins will not cure many kinds of elastomers, such as saturated elastomeric polymers.

It has now been found that sulfur and a polyhaloaliphatic compound will cure (cross link) crystalline polymers as well as amorphous or rubbery polymers. This cross linking of polymers is desirable since, for example, it produces a product which has greater resistance to heat and greater resistance to solvation by oils or oil based solvents. Among the crystalline polymers contemplated by this invention are crystalline C -C homopolymers and copolymers such as polyethylene, polypropylene and polyethylene-polypropylene block copolymers. These are all alpha olefin hydrocarbon polymers.

In particular, to 100 parts of polymer is added between about 0.1 to parts by weight of sulfur, preferably 0.5 to 5 parts by weight, and about 0.2 to 30 parts by weight of the polyhaloaliphatic compound, preferably 0.5 to 10 parts by weight. The resulting mixture is then heated to yield a cured or cross linked product. To further improve the process, zinc oxide, various fillers, and metallic accelerators, such as FeCl may be added to the mixture. Furthermore, improved results may also be obtained by masterbatching the polymer and the polyhaloaliphatic compounds of this invention prior to curing.

The polymers to which the present invention is applicable inculde high unsaturation rubbers such as natural rubber, polybutadiene, nitrile rubber (a copolymer of acrylonitrile and butadiene), SBR (a copolymer of styrene and butadiene), and polychloroprene (a homopolymer of 2-chloro-'butadiene-1,3). The invention is also applicable to low unsaturation rubbers such as butyl rubber (a co- Sttes Patent polymer of a major portion of a C -C isoolefin with a minor portion of a C -C multiolefin), and chlorobutyl (chlorinated butyl rubber). Finally, and most surprisingly, elastomers and crystalline polymers of no unsaturation may be cured by the present invention. These include Vistanex (polyisobutylene) and the low pressure, substantially amorphous copolymers of ethylene and other alpha olefins. The copolymers thus include C to C alpha olefins such as propylene, l-butene, and l-pentene. Propylene is particularly preferred as the other alpha olefin. The process for producing these low pressure copolymers is generally described in the literature, e.g., see U.K. Patent 856,736, Scientific American, September 1957, pages 98 et seq., and page 6 of copending application Ser. No. 116,938, filed June 14, 1961. The invention is also applicable to amorphous or crystalline C -C alpha olefins homopolymers such as polyethylene and polypropylene, to blends of various of the above listed polymers, and to copolymers containing more than two kinds of monomers, such as terpolymers and tetrapolymers. Finally it is to be noted that the use of mineral-filled or oil-extended polymers will yield an improved product.

The polyhaloaliphatic compounds which may be used in this invention include the polyhaloalkanes and the polyhalocyclomonoalkenes. By polyhaloalkanes is meant C C alkanes which have been substituted with halogen to such an extent that they contain not more than one hydrogen atom per molecule. Representative examples of these compounds include C01 CHCl hexachloroethane, heptachloropropane, octachloropropane, the bromine and iodine analogs of these compounds, and compounds of mixed halogenation such as dichloro-dibromomethane. Especially preferred are hexachloroethane, heptachloropropane, and octachloropropane.

The polyhalomonoalkenes which may be used in this invention include cyclomonoolefins which contain between 3 and 20 ring carbon atoms and which have been substituted with halogen atoms to such an extent that they contain not more than one hydrogen atom per molecule. Especially preferred of this group is octachlorocyclopentene.

Other polyhaloaliphatic compounds which may be used include the C to C cycloalkanes which have been halogenated to such an extent that they include no more than 1 hydrogen atom per molecule.

It is desirable in this invention to further include zinc oxide in the curing mixture in an amount of from O to 20 parts per 100 parts of polymer.

Fillers are also desirable and a variety of carbon blacks, clays, silicas, and whitings may be used. Best results are obtained with semi-reinforcing or highly reinforcing furnace and channel carbon blacks such as those designated commercially as SAF, SRF, HAF, EPC, and MPC types of carbon blacks. The amount of filler used can be from 0 to 200 parts by weight, but preferably 20 to parts per parts of elastomer is used.

The metallic accelerators which are useful in this invention include metals, inorganic metallic compounds, and metallic salts of carboxylic acids. Preferred substances are aluminum powder, the metal halides, oxides, sulfides, ammonium sulfates and the metallic salts of alkyl monoand dicarboxylic acids. Especially preferred are iron oxide 3e 2 (ferrous and ferric), iron chloride, aluminum chloride, iron octasol (iron 2-ethyl-hexoate) and iron dl-stearate. 1 2 3 4 These substances may be present in amounts of about 0.0001 to 10 parts by Weight, preferably 05 to 5 p l a: gugger, -gag .l 100 100 n... i a u er, 0 100 These accelerators, it is to be noted, have surprlslngy 5 HAFCMbOnB1ack 50 50 50 50 greater effectiveness when the zinc oxide 18 absent fr m t Sulfur" 2 2 2 2 curing mixture. g gggg g -g 2 2 The cross linking of the polymers may be effecte by Octachloropropane .2 5 5 5 thorough contacting of the polymer with a curlng mixgg /ggpert esz ture, e.g., on a rubber mill, or in a Banbury mixer, and Tensile, p.s.i 870 subjecting the resulting mixture to temperatures of 250 39 100 to 450 F., preferably 280 to 400 F., for from 1 to 180 Tensile, p.s.i 410 2,040 g 1, goo minutes, preferably 1 to 90 minutes. P 1P 680 A more referred method is to mix the olymer and Tensile, p.s.i 500 3,480 2, 430

p E1 (7' t 890 d curing agent with or wlthout sulfur or other addltlves 3 15; perm 650 U 650 in a masterbatch and then simply heat the resulting com- Tensile, p.s.i 660 3,500 l00 2,520 position of matter to a curing temperature as needed 9 }'j 850 600 900 600 (other additives may be mixed with the masterbatch just Tensile, p.s.i 970 3,830 110 2,750 prior to heating). The advantages of producing the cross- 9 fif 800 580 900 600 linked product in this manner include the following: (1) gensile, psi 1, 770 3, 730 (g) 2, s90 mixing time is reduced, (2) the addition of the curing 750 500 O 580 agent to the masterbatch lowers the Mooney viscosity of EH 1e 1 1e 01 rm d M Vol/A1: H C t S 1y ne-propy e1 cop yme a GVVI 1 on all! the mlxture and thereby faclhtates the Processmg of the 49 mole percent propylene units, intrinsic viscosity, 5.2 iii d ec alin at 135 polymer i l l (1 n1 VOCl lAlEtCl o t y ene-propy ene COPO ymer ma e '1 3 g. 011 31115 t T1211?) lnvefntlon ai'tid tIl -1S i fi ag W111 l T L g i lgsmglvegcent propylene units;intrilisic visc0sity,3.93 in decalin at 135 s 00 y re erence o e o owlng examp es. e a a o 1 O N d S.N. 177,179 are repeated herein as the curing of cer- 23531 33 late (6% uodex Pm co)anlronsaltoftanon tain elastomers is analogous to the cross linking of crystalline polymers Exam le 2 Example 1 p The elastomeric ethylene-propylene copolymer were Various inorganic metal salts were utilized as accelervulcanized with the use of octachloropropane. Details and aims for the Vulcanllatlon of elastomenc y p p results are given in the following table. In this and the ene copolymers with octachlorocyclopentene used as the following tables the parts are by weight per 100 parts of 35 vulcanizing agent. As can be seen from the following polymer, table, these agents are highly effective accelerators.

A B o D E F G EP Rubber, F-4734 e 100 100 100 100 100 100 100 EP Rubber, MD-460 b HAF Carbon Black 50 50 50 50 50 50 Ewing-" n a 1 1 1 1 inc xi e n 2 2 2 2 0 ct achlol'ocyclopentene 5 5 5 5 5 5 5 Inorganic Metal Salt. None AlCl FeCla FeCla.6H2O SnCl 5H10 ZnCl @3012 FEB 5 5 5 5 5 '5 Cure: minutes at 335 F.

Tensile, p.s.i 310 2, 260 2, 300 2, 500 1,700 1,890 l, 500 Elongatloli, percent e. 900 550 350 480 650 780 650 H I J K L M N EP F4734 Rubber, 100 EP Rubber, MD-460 100 100 100 100 100 HAF Carbon Black 5O 50 50 5O 50 5O 50 Sulfur l. 1 i 2 2 2 2 2 Zinc Oxide 2 2 2 2 2 2 2 Octachlorocyclopentene. 5 5 5 5 5 5 5 Inorganic Metal Salt.-. BaCl2.2H2O COClz.6HzO None FeClz.4HzO HgClz AlBIz FGNHKSOO: PHR 5 5 5 5 .5 5 Cure: 60 minutes at 335 Tensile pvsi 1,190 1, 000 360 2, 240 1,720 1,530 2' 00 Elongation, percent 780 580 1, 000+ 480 700 600 650 a Ethylene-propylene oopolymer, which contains 30 mol percent propylene units; inherent viscosity of 2.9 in decalin at C. b Ethylene-propylene copolyiner, which has been (leashed and contains Ethyl Antioxidant 702; contains 58% by mole of propylene units; inherent,

viscosity of 3.93 in dccalin at 135 C.

Example 3 7 Various organic metal salts are shown to be effective accelerators for the vulcanization of a rubbery ethylenepropylene copolymer with octachlorocyclopentene used as the vulcanizing agent. Details and results are as fol- Example 5 Miscellaneous metal compounds as accelerators for octachlorocyclopentene vulcanization are shown to be effective in the following table. It is to be noted that these 5 accelerators have a much greater effect when zinc oxide lows:

A B C D E F G EP Rubber, MD-460 100 100 100 100 100 100 100 HAF Carbon Black 50 50 50 50 50 50 50 Sulfur 2 2 2 2 2 2 2 Zinc Oxide 2 2 2 2 2 2 2 Octachlorocyclopentene 5 5 5 5 5 5 5 Organic Metal Salt e Iron Iron Iron Iron Iron Iron naphthenate octasol distearate nuolate octoate oxalate PHR- 5 5 5 5 5 5 Cure: 60 Minutes at 335 F.-

ensile, p.s.i 360 2, 520 3, 000 3, 120 2, 160 2, 390 1, 950 Elongation, percent" 1, 000+ 600 700 650 680 550 580 Tensile, p.s.i 1, 200 2, 050 2, 930 2, 980 1, 790 2, 120 2, 240 Elongation, percent 930 500 750 600 580 550 500 H I J K L M N E? Rubber, MD-460 a 100 100 100 100 100 100 100 HAF Carbon Blaok 50 50 50 50 50 50 50 Sulfur 2 2 2 2 2 2 2 Zinc Oxide 2 2 2 2 2 2 2 Octachlorocyclopentene 5 5 5 5 5 5 5 Organic Metal Salt Aluminum Aluminum Aluminum Cobalt Manganese Lead Cerium stearate octoate laurate naphthenate naphthenate stearate naphthenate PHR 5 5 5 5 5 5 5 Cure: 60 Minutes at 335 F.

Tensile, p.s.i 2, 080 850 1, 350 1, 440 590 1, 090 710 Elongation, percent 1, 000 850 950 780 1, 000 1, 000+ 1, 000+ Cure: 6 Minutes at 400 F.-

Tensile, p.s.i 2, 400 2, 500 2, 590 1, 960 1, 960 2, 030 1, 880 Elongation, percent 700 580 650 650 650 950 750 Ethylene-propylene copolymer, which has been deashed and contains Ethyl Antioxidant 702; contains 58 mole percent propylene units: inherent viscosity of 3.93 in decalin at 135 0.

Example 4 The concentration effect of ferric chloride, a typical accelerating agent, is shown in the following table:

is absent from the curing mixture (compare run F with runs C or A B C D E? Rubber, MD-460 HM l 100 100 100 100 HAF Carbon Black. 50 50 50 Sulfur- 2 2 2 2 45 Zinc Oxide 2 2 2 2 Octachlorocyclopentene 5 5 5 5 FeClg (anhydrous) None 0. 05 0.1 1.0 Cure: Minutes at 335 F Tensile, p.s.i 1, 2, 720 3, 400 3, 160 Elongation, percent 93 700 720 480 50 B Ethylene-propylene rubber, which was deashed and contained Ethyl Antioxidant 702; contained 58 mole percent propylene units with inherent viscosity of 4.26 as determined in decalin at 135 C.

A B C D E F G H I J K L EP Rubber, MD460= 100 100 100 100 100 100 100 100 None None None None EP Rubber, F-4723 None None None None None 'None None None 0 100 100 100 HAF Carbon Black 50 50 50 50 50 50 50 v 50 50 50 50 Sulfur 2 2 2 2 2 2 2 1 1 1 1 Zinc Oxide 2 None None None None 2 2 2 2 2 2 2 Octachlorocyclopentene 5 5 5 5 5 5 5 5 5 v 5 5 Metal Compound None None Iron Iron None Iron T101 S018 None A Aluminum Aluminum oxide oxide oxide Iso-propoxide powder PH R- 5 5 5 5 5 5 5 Tall Oil 0 None None None 5 5 None None None None None None None Cure: 30 mins. at 307 F. V

Tensile, p.s.i 1,500 2, 500 0 Elongation, percent 750 700 0 Cure: 30 mins. at 320 F.

Tensile, p.s.i Not 2, 870 2, 630 50 cured Elongation, percent 500 580 100 Cure: 60 mine. at 335 F.-

Tensile, p.s.i 360 No; 2, 600 2, 690 100 1, 260 710 1, 060 310 810 1, 050 1, 050

cure Elongation, percent 1, 000+ 350 600 350 950 1, 000+ 1000 900 680 850 700 l Ethylene-propylene copolyrner, which contains 58 mole percent propylene units with inherent viscosity of 3.93 and contains Ethyl Antioxidant 702 and has been deashed.

b Contains no antioxidant and has 70 mole percent ethylene units in the rubber with inherent viscosity of 2.62 as determined in decalm at C. and has not been deashed.

s From Arizona Chemical 00., with trade name of Acintol FA #1," which contains less than 0.001% ash; 4% rosin acid; 4% unsaponifiables; 92% fattyacids (contains conjugated linoleic acid, 8%; unconjugated linoleic acid, 36%; oleic acid, 50%; saturated acids, 6%). ASTM D803 tests=acid N o. 191 gravity, 0.9065.

; saponification No. 195; Iodine No. 135; specific 7 Example 6 In the following example the effect of various non-black fillers is shown in the vulcanization of rubbery ethylenepropylcne copolymers.

propylene copolyrners prepared by a solution process is shown in the following table:

A B C D E Composition Synthesis. n

(1) EP Rubber Solltion 1 -4723, g 500 500 500 500 500 (2) Octachlorocyclopentene, g 1 2 15 30 100 (3) Sodium Stearate, g 0.3 0.3 0. 3 0.3 0.3 (4) Product, Dry Rubber, g 27.5 27.0 40. 5 51. 5 113. 5 (5) Octachlorocyelopentene in Product (Based on amount used), percent 3. 64 11.11 37. 04 58. 25 88. 11 Analysis:

(6) Chlorine Found in Product, wt. percent. 2.61 658 31.17 39. 85 62.06 (7) Equivalent achlorocyclopentene,

wt. percent. 3.16 7. 97 37. 75 48. 26 75.15 CompoundiugCornpo 100; HAF Carbon Black, 50; Sulfur, 2; Zinc Oxide, 2:

Cure: 30 minutes at 33 F.-

Tensile, p.s.i, 190 440 2, 130 Elongation, perce 700 1, 000+ 280 Cure: 60 minutes at 335 Tensile, p.s.i 400 2, 690 1, 780 Elongation, percent 1, 000+ 600 130 Cure: 60 minutes at 320 Tensile, p.s.i 190 470 2, 230 Elongation, percent 1, 000+ 1, 000+ 250 Cure: 6 minutes at 400 F.

Tensile, p.s.i 1, 520 2,610 1, 730 Elongation, percent 900 300 O Dilution of Composition with (8) Corresponding Composition, g 9.1 3.2 (9) Pure EP Rubber, F4723, 80 90.9 96.8 (10) Equivalent Octachloroeyclopentene (wt. percent) (7. 5) (4. 3) (2. 4) Compounding-Diluted Composition, 100; HAF Carbon Black, 50; Sulfur, 2; Zinc Oxide 2:

Cure: minutes at 335 F.-

lensile, p s i 360 240 260 Elongation, percent 1, 000+ 1, 000+ 1, 000+ Cure: 60 minutes at 335 F Tensile, p.s.i 1, 730 840 530 Elongation, percent 980 1, 000+ 1, 000+ Cure: 60 minutes at 320 F.

Tensile, p.s.i 330 260 240 Elongation, percent 1, 000+ 1, 000+ 1,000+ Cure: 6 minutes at 400 F.-

Tensile, p.s.i 3,160 2, 650 1, 540 Elongation, percent 550 660 1, 000+ l The rubber solution and octachlorocyclopentenc were mixed thoroughly and then added into one lliJBl of hot water at about 180 F. with stirring. This temperature was maind oil so as to produce a workable d in air at room temperature.

of ethylenepropylene copolymer which inherent viscosity of 2.4 as determined in decalln at 135 C.

A B C D EP Rubber, MD-460 a 100 EP Rubber, MD-460 HM b 100 100 100 HiSi1/233 50 Dixie Clay 50 Zeolex 7A 50 Sulfur 2 2 2 2 Zinc Oxide 2 2 2 2 Octachlorocyclopentene. 5 5 5 5 FeCl; (anhydrous) None 0. 2 0. 2 0. 2 Calcium Stearate 1 1 1 Cure: 60 minutes at 335 F Tensile, p 3, 200 3, 960 1, 980 2, 620

Elongat 740 650 900 700 Example 7 The preparation and vulcanization of compositions of matter comprising octachlorocyclopentene and ethylene- Example 8 Parts of octachlorocycl-opentene Mooney plasticity mixed into 100 parts of (8 min./212F.) ethylene-propylene rubber:

None (control) 48 2 46 5 i 44 10 41 20 37 50 27 85 19 Example A B C D E F Polyethylene e 100 100 100 None None None Polypropylene None None None 100 100 100 AF Carbon Black. 50 50 50 50 50 50 fur l l 1 1 1 Zinc Oxide 0 2 2 2 2 2 Octachlorocyclopentene 0 0 0 3 10 Cora: 30 films. at 320 F 2 000 2 190 ens e, p.s.1 Elongation, percent l00 l0o o cum-m sample Cure: 30 mins. at 335 F.-

Tensile, p.s.i 1, 790 1, 850 2, 270 780 1, 820 1, 950 Elongation, percent 100 200 200 0 580 600 Cure: 60 mine. at 335 F Tensile, p.s.i 1, 770 1, 960 2, 500 700 2, 140 2, 780 Elongation, percent 100 180 150 150 500 450 Gel Content, percent a 27 100 24. 4 49. 0 M3 Bakelite Polyethylene (DYNH-3)mixed on rubber mill at 200 F.

b Amorphous: molecular weight, 270,000.

Determined by heating in decalin at 135 C. at 0.1% cone. for one hour, and then filtering through a 325 mesh screen and weighing the insoluble residue after drying.

Example 10 Example 12 The high pressure polyethylene and amorphous poly- In the following table, it is shown that octachlorocyclopropylene of Example 9 are shown to be curable with pentene is also useful for vulcanizing blends of butyl rubhexachloroethane. Details and results are as follows: her with other rubbers.

A B C D E Polyethylene I 100 100 100 None None Polypropylene None None None 100 100 HAF Carbon Black 50 50 50 50 50 Sulfur 0 1 1 1 1 Zinc Oxide" o 2 2 2 2 Hexachloroetha 0 0 10 0 5 ure 30 mins. at 3 Tensile, p.s.i. 1,820 2, 000 1, 950 0 1, 470

Elongation, perce 100 100 180 0 150 Cure: 30 mins. at 335 F Tensile, p.s.i 1, 790 1, 850 1, 950 780 2,060

Elongation, perce 100 200 130' 0 550 Cure: 60 mins. at 335 F Tensile, p.s.l 1,770 1,960 1, 950 700 2, 280

Elongation, perce 100 180 100 150 550 Gel Content, percent 27 25 97 24.4

n Bakelite Polyethylene (D YNH-3)--mlxed on rubber mill at 200 F.

b Amorphous: M.W., 270,000.

e Determined by heating in decalin at 135 C. at 0.1% cone. for one hour, and then filtering through a 325 mesh screen and weighing the insoluble residue after drying.

Example 11 In the following table, it is shown that octachlorocyclopentene will effectively vulcanize unsaturated rubbers such as butyl-SBR blends:

A B C D E F G H I J Butyl 218 100 50 25 None 75 50 25 None SBB 1500 b None 25 so 75 100 None 25 so 75 100 HAF Carbon Black- 50 50 5o 50 so 50 so 50 so 50 Sulfur 2 2 2 2 2 2 2 2 2 2 Octachloroeyclopenten None None None None None 5 5 5 5 5 Cure: 30 mins. at 320 F.

Tensile, p s i 530 260 170 110 l 700 480 l, 000 2, 250 2, 48') Elongatlon, perc l 1, 000+ 600 650 700 600 630 400 250 330 450 Curel: 60 llnins. at 335 F ensi e, p. s. i 280 470 1,160 2 3 000 2 090 790 1 980 2 190 2 750 Elongation, perc 1,000+ 400 280 '380 '550 4ao V 100 '150 '200 I A commercial grade of butyl rubber (all lsobutylene-isoprene copolymer produced by the Enjay Chemlcal'Company). b A commercial type of butadiene-styrene copolymer. l

A B O D E F Butyl 218, g. 100 100 100 75 75 50 Other rubber Smoked sheet Smoked sheet Smoked sheet G... 25 5O HAF Carbon Black 5O 50 50 50 50 50 Sulfur 2 2 2 2 2 2 Zinc Ox 2 2 2 2 Octachlorocyclop 5 2 5 5 Cure: min. at 320 F.-

Tensile, p.s.i 530 700 1, 910 280 670 1,280 Elongation, Percent. 100+ 630 600 500 280 200 Cure: 30 min at 335 Tensile, p.s.l 2, 700 350 560 1, 090 Elongation, Percent 530 700 250 200 Cure: 60 min. at 335 F.

Tensile, p.s.i 280 Elongation, Percent 1, 000+ G H I .T K L M Butyl 2i8, gm 75 75 75 75 76 75 75 Other Rubber Hypalon Hypalon 40 e "cis-4 polyole-4 polyd Paracrll G Paracril C Neoprene W butadiene butadiene 25 25 25 25 25 25 50 50 50 50 50 50 50 2 2 2 -2 2 2 2 Zinc Oxide 2 2 2 2 2 2 2 Octachlorocyclope 2 2 2 2 Cure: 30 min. at 320 F.

Tensile, p.s.1 580 570 290 870 770 1,000 l, 660 Elongation, Percent 50 50 330 230 430 230 130 Cure: 30 min. at 335 F.-

Tensile, p.s.i 440 670 400 820 830 1,110 1, 480 Elongation, Percen 0 0 400 150 250 130 100 Cure: min. at 335 Tensile, p.s.l Elongation, Per nt e A commercial grade of butyl rubber (an isobutylene-isoprene c0- polymer produced by the Enjay Chemical b A chlorosulfonated polyethylene (E. I.

Company) DuPont de Nemours Company c A commercial poly-cls 1,4-butadiene (Phillips Chemical Company).

States Rubber Company) d A commercial copolyrner of butadiene and acrylonitrlle (United e A commercial polychloroprene (E. I. duPont {de Nemours Com- Example 13 i a In the following table, it is shown that chlorinated paraffin Wax is not a vulcanizing agent for ethy1ene pm polyenes are not efiectrve vulcanlzmg agents for ethylenepylene rubbery copolyrners: propylene A B 60 A B 0 EP Rubber F-3616 100 100 EP Rubber, 100 100 A g Black 50 50 5O na r Carbon Black" 52 5 81mm: 1 1 1 -a- 2 2 Zmc Oxide .s 2 2 2 .5 x1 None 10 Perhalocyclopolyene None A 10 b 10 fif 5 Cure: 30 minutes at 280 F.-

Tensile Strength, p.s.i 370 410 f n fg2 Elongation percent 600 800 a" Cure- 60 minutes at 335 F f 30 flmuute-s at 320 F 450 520 500 ensie p E12 1? til ri ge t SIL- Elongation, percent 630 550 750 g p Cure: 60 minutes at 335 F.

Tensile psi 410 650 500 n 49 mole percent propylene units. Inherent viscosity of 5.7 as deter Elongation percent 580 450 730 mined in decalin at C. (Catalyst=VCl /Al(C H m) b Diamond Alkali Company Chlorowax paraffin wax.

Example 14 70a resinous ch lorinated e Hexaehlorocylopentadiene. b Hexachlorobenzene.

*Ethylenepropylene rubber, which cont propylene units and ains about 49 mole percent ty of 5.7 as determined in Example 15 In the following table, it is shown that perhaloalkenes are not effective vulcanizing agents for ethylene-propylene rubber:

EP Rubber, F36l6* 100 100 100 100 100 HAF Carbon Black O 50 50 50 50 Sulfur 1 1 1 1 l Zinc Oxide 2 2 2 2 2 Perhaloalkene None PHR None 1O Cure: rnins. at 280 F.-

Tensile, p.w.i 370 650 520 550 Elongation, percent 600 750 650 700 Cure: 30 rnins. at 320 F.

Tensile, psi 450 660 630 600 Elongation, perccnt Cure: 60 nins. at 335 F e 'Ietrabromoethylene.

b Hexachloropropene.

= l,1,2-trichl0ro-3,3,3-trifiuoropropene.

d Hexachlorobutadiene.

Ethylene-propylene rubber, which contains about 49 mole percent propylene units and has an inherent viscosity of 5.7 as determined in decalin at 135 0.; prepared with VCI IAKC H M complex catalyst.

Example 16 In the following table, the elfect of the number of hydrogen atoms in the polyhaloaliphatic molecule on the vulcanization of ethylene-propylene rubber is shown. As can be seen, only those molecules with no more than one hydrogen atom are eifective.

1 4 Example 1 7 In the following table it is shown that low pressure crystalline (isotactic) polypropylene may be cross linked with the use of sulfur and octachlorocyclopentene. The cross linked product contains gel while the non-cross linked polymer does not.

H Isotaetic polypropylenecom mercial polymer produced by low pressure process. I.V. in decalin at 135 0., 3.08.

b 0 O C P Octachlorocyclop entene.

" Cured in micro pads and tested with Scott micro tensile machine.

d The gel was determined by heating the polymer in decalin (1 g./1.) at 135 C. for 1 hr. with a reflux condenser. The decalin solution was filtered hot over a 375 mesh screen: the gel was dried and the filtrate (sol) was run for viscosity. 7

Example 18 In the following table it is shown that low pressure, crystalline polyethylene may be cross linked with sulfur and octachlorocyclopentene.

A 13 C D E F G F-3616 EP Rubber 100 100 I00 100 I00 CP-2 EP Rubberl' 100 100 HAF Carbon Black 50 50 50 50 Sulfur 1 1 l 1 2 2 Zinc Oxide.. 2 2 2 2 5 5 Polyhaloaliphatim None 10 5. 9 None Cure: 30 minutes at 280 F.-

Tensile, p.s.i 370 630 630 590 390 710 370 Elongation, percent. 600 650 750 780 650 600 480 Cure: 30 minutes at 320 F.- Tensile, psi; 450 1, 030 470 800 440 640 Elongation, percent. 630 450 600 750 700 700 Cure: minutes at 335 Tensile, p.s.i s 410 1,050 900 1,110 390 320 Elongation, percent 580 450 600 600 630 550 A. One Hydrogen B Iodoiorm.

b Pentabromoethane.

v 1,1,1,2,2,3,3-heptachl0ropropane.

B. Two Hydrogens d l,1,2,2-tetrachloroethane.

0. Six Hydrogens B 1,2,3,4,5,fi-hexachlorocyclohexane,

Ethylene-propylene rubber, which contains about 49 mole percent propylene units and has an inherent viscosity of 5.7 as determined in decalin at 135 0.; prepared with VCh/ (G6H1-'i)3 complex catalyst.

TEthylene-propylene rubber which contains about 37 mole percent propylene units and has an inherent viscosity of 4.4 as determined in tetralin at 135 0.; prepared with VCls/Al (isobutyl); complex catalyst.

A B C D E F Polyethylene a 100 100 100 100 100 Sulfur 1 0 1 0 0 l 1 0 2 0 2 O 2 0 0 5 5 5 5 Cure: 400 F./30

B Low pressure crystalline polyethyleneBaton Rouge AMP Run #34; Density, 0.923;

Soft Point, 132 0.; M.P

., 185 C. Intrinsic Viscosity in decalin at 0., 2.50.

b OCCP= Octachlorocyclopentene.

Cured in micro pads and tested with Scott micro tensile machine.

d The gel was determined by heating the polymer in decalin (1 g./l.) at 135 C. for 1 hr. with a reflux condenser. The decalin solution was filtered hot over a 375 mesh screen: The gel was dried and filtrate (sol) was run for viscosity.

= Indeterminate.

15 Example 19 In the following tables various curing agents of this nvention are shown to cross link two crystalline polyners.

16 tains 1 to 200 parts of filler and 1 to 20 parts of zinc oxide per 100 parts of polymer.

7. A method for cross linking a C -C alpha olefin hydrocarbon crystalline polymer which comprises A ants used 5 (a) mixing said polymer with sulfur and a polyhalog aliphatic compound selected from the class consist- Ia) hexachloroethane ing of: (b) octachloropropane (1) C C polyhaloalkanes containing no more (c) heptachloropropane than one hydrogen atom wherein the halogen is (d) octachlorocyclopentene selected from the class consisting of chlorine, (e) iodoform bromine and iodine, and

Sample No. 1 2 3 4 5 6 7 8 9 I 10 11 12 Polyethylene 1 100 100 100 100 100 100 100 100 100 100 100 100 Philblack O None None None None None None 50 50 50 50 50 50 Sulfur 1 1 1 1 1 1 1 1 1 1 1 1 regos 5 5 5 5 5 5 5 5 5 5 5 5 Agent, 1765 -1 50-11 None (a) (b) (c) (d) (e) None (a) (b) (c) (d) (e) Wt None 5 5 5 5 5 None 5 5 5 5 5 Cure: 400 F./'

Tensile, p.s.i. yield 792 1, 219 432 Elong, percent yield 50 23 N.O Cure: 400 F./6-

Tensile, p.s.i. yield 3,063 2, 77s 2, 405 1, 44s 2, 514 2, 377 1,096 1, 400 1, 576 1,382 1,821 1,611 Elong, percent yield 22 27 26 25 28 5 4 1 5 2 2 Gel, percent 2 1. 6 1. 0 84. 9 9. 2 95. 4 82. 3 32. 6 51. 4 67. 0 58. 9 79. 4 86. 5 Intrinsic Viscosity 3 2. 1

1 Density, 0.9476; tensile at 2/rninute, 2,940 p.s.i. yield; elongation, 17% yield; melt index, 1.2. 3 Determined in decalin at 135 C. at 1 g./1. for 1 hr.; filtered over a 375 mesh screen and dried. Determined in decalin at 135 C. at 0.5 g./l. for 1 hr.', filtered over 375 mesh screen and dried.

Sample No. 1 2 3 h 4 5 6 l 7 8 9 l 10 11 12 Polypropylene 1 100 100 100 100 100 100 100 100 100 100 100 Philblack O None None None None None 50 50 50 50 50 50 Sulfur- 1 1 1 1 1 1 1 1 1 1 1 Fe O3 5 5 5 5 5 5 5 5 5 5 5 Agent (a) (e) None (at) 5 5 5 5 5 None 5 5 5 5 5 Cure: 400 F76- Tensile, p.s.i. yield 3, 675 3, 514 700 863 1, 470 1,141 1, 281 728 1, 034 1, 397 694 178 Elong., percent yield 40 29 127 372 48 50 4 6 10 11 5 11 Percent Gel 2 1. 6 62. 9 40. 8 85. 7 100 60. 4 32. 0 49. 6 58. 0 62. 7 67. 8

1 Isotactic low pressure polypropylene: density, 0.9102; tensile at2/1;ninute, 4,480p.s.i. yield; elongation, 17% yield; melt index, 0.36; intrinsic viscosity 1 Determined in decalin at 135 C. at 1 g.[l. for

The advantages of this invention will be apparent to those skilled in the art. Cured polymers are provided of high tensile strength, having substantially no odor, and with improved physical characteristics. The cross linking agents herein disclosed have been found to cure not only unsaturated polymers but also polymers having no unsaturation at all.

This invention has been described in connection with certainspecific embodiments thereof; however, it should be understood that these are by way of example rather than by way of limitation and it is not intended that the invention be restricted thereby.

What is claimed is:

1. A curable composition of matter comprising sulfur, C -C alpha olefin hydrocarbon crystalline polymer and a polyhalocyclomonoalkene containing no more than one hydrogen atom and up to 20 ring carbon atoms wherein the halogen is selected from the class consisting of chlorine, bromine, and iodine.

2. The composition of claim 1 crystalline polypropylene.

3. The composition of claim 1 wherein the polymer is crystalline polyethylene.

4. The composition of claim 1 wherein the polyhaloaliphatic compound is octachlorocyclopentene.

5. The composition of claim 2. wherein the polyhaloaliphatic compound is octachlorocyclopentene.

6. The composition of claim 4 which additionally conwherein the polymer is 1 hr.; filtered through a 375 mesh screen and dried.

(2) polyhalocyclomonoalkenes containing no more than one hydrogen atom and from 3 to 20 ring carbon atoms wherein the halogen is selected from the class consisting of chlorine, bromine, and iodine, and

(b) heating to a curing temperature.

8. The method of claim 7 wherein the polyhaloaliphatic compound is octachlorocyclopentene.

9. The method of claim 7 wherein the polyhaloaliphatic compound is a C C polyhaloalkane containing no more than one hydrogen atom wherein the halogen is selected from the class consisting of chlorine, bromine, and iodine.

10. The method of claim 8 wherein the polymer is crystalline polypropylene.

11. The method of claim crystalline polyethylene.

8 wherein the polymer is References Cited UNITED STATES PATENTS 3,012,996 12/1961 McFarland 260-338 3,012,020 12/1961 Kirk ct al. 26-0--41 3,141,867 7/1964- Smith 260-9'4.9 3,227,664 1/1966 Blades et al. 260-333 MORRIS LIEBMAN, Primary Examiner. I. S. WALDRON, K. B. CLARKE, Assistant Examiners. 

1. A CURABLE COMPOSITION OF MATTER COMPRISING SULFUR, C2-C5 ALPHA OLEFIN HYDROCARBON CRYSTALLINE POLYMER AND A POLYHALOCYCLOMOALKENE CONTAINING NO MORE THAN ONE HYDROGEN ATOM AND UP TO 20 RING CARBON ATOMS WHEREIN THE HALOGEN IS SELECTED FROM THE CLASS CONSISTING OF CHLORINE, BROMINE, AND IODINE. 